The present invention is concerned with mold handling apparatus.
In the molding of articles in a mold cavity provided by assembled portions of a split mold (for example, in injection molding), it is necessary when an article has been molded to separate the mold portions (open the mold) so that the molded article can be removed from the mold cavity. The mold portions have then to be brought together again (the mold closed) before a further article can be molded in the mold cavity.
Mold handling apparatus of many kinds has been suggested which serves to automatically bring together and separate the two portions of a two-part split mold for repeated molding of an article in the mold cavity provided thereby. In the field of injection molding of plastics materials, mold handling apparatus may be provided embodied in an injection molding machine, which also injects plastics material into the mold cavity after the mold has been closed, or it may be provided as free-standing apparatus to which a separate plastics injection unit can be brought.
It has been found that there is a requirement for a mold handling apparatus which is especially suitable for use in the manufacture of large components molded from a polyurethane plastics material. It is believed that such apparatus should ideally be arranged to allow for:
1. CLEAR AND CONVENIENT ACCESS BY AN OPERATOR TO EACH MOLD PORTION WHEN THE MOLD HAS BEEN OPENED, AND ESPECIALLY TO ONE PORTION OF A TWO-PORTION MOLD, FOR THE PURPOSES OF, FOR EXAMPLE, REMOVING A MOLDED ARTICLE THEREFROM, CLEANING AND TREATING THE MOLD PORTION, OR PLACING REINFORCING MATERIAL (WHICH IS TO BE EMBODIED IN A MOLDING) IN THE MOLD PORTION,
2. A WIDE VARIETY OF MOLD SHAPES AND SIZES TO BE ACCOMMODATED BY THE APPARATUS (INCLUDING RELATIVELY LONG AND NARROW MOLD FORMS),
3. MOLD SUPPORT MEANS OF THE APPARATUS TO BE PIVOTAL SO THAT THE ANGLE OF DISPOSITION OF A CLOSED MOLD CAN BE VARIED (SO THAT, FOR EXAMPLE, A MOST SUITABLE DISPOSITION OF THE MOLD CAN BE ACHIEVED FOR A WIDE VARIETY OF MOLD FORMS),
4. IT TO BE UNNECESSARY FOR AN OPERATOR TO WORK IN POTENTIALLY DANGEROUS SITUATIONS AS, FOR EXAMPLE, WITH HIS HANDS BETWEEN OPPOSED MOLD SUPPORT MEANS WHICH COULD CLOSE TO TRAP HIS HANDS, AND
5 AN OPERATOR TO WORK SUBSTANTIALLY ENTIRELY FROM AN OPPOSITE SIDE OF THE APPARATUS FROM A PLASTICS INJECTION UNIT, WHICH UNIT MAY BE ARRANGED TO MOVE TO EACH IN TURN OF A PLURALITY OF MOLD HANDLING APPARATUS, AND THUS BE A HAZARD TO THE OPERATOR.
When molding some plastics materials in split molds it may be necessary for very large clamping forces to be applied to the mold portions during injection of the plastics material into the mold cavity, and mold handling apparatus suitable for use in such circumstances, accordingly, tends to be of a heavy and rigid construction such as permits the large clamping forces to be applied. Commonly, the mold support means on which the mold portions are mounted are interconnected by tie bars to provide a sufficiently rigid and strong structure for the large clamping forces to be applied. However, the tie bars and other machine elements necessitated by the demand for very large clamping forces can tend to result in the mold support means, and mold portions thereon, being generally rather obstructed, to the inconvenience of an operator and leading to severe limitations on the variety of mold shapes and sizes which can be accommodated on the mold support means.
In the molding of polyurethane plastics materials, for example, such very large clamping forces are not necessarily required and it is believed that, accordingly, apparatus construction need not be so determined by high demands for rigidity and strength. It is considered that advantage can be taken of this factor to provide a mold handling apparatus which provides advantages over presently proposed apparatuses, both to an operator and generally in construction and operation.
It is, therefore, one of the various objects of the present invention to provide an improved mold handling apparatus which may be especially suitable for use in the manufacture of articles molded in a wide variety of shapes and sizes from a polyurethane plastics material, and which permits generally convenient and safe working conditions for an operator.